Paint System
Qt's paint system enables painting on screen and print devices using the same API, and is primarily based on the QPainter, QPaintDevice, and QPaintEngine classes.
QPainter is used to perform drawing operations, QPaintDevice is an abstraction of a two-dimensional space that can be painted on using a QPainter, and QPaintEngine provides the interface that the painter uses to draw onto different types of devices. The QPaintEngine class is used internally by QPainter and QPaintDevice, and is hidden from application programmers unless they create their own device type.
The main benefit of this approach is that all painting follows the same painting pipeline making it easy to add support for new features and providing default implementations for unsupported ones.
Topics
- Classes for Painting
- Paint Devices and Backends
- Drawing and Filling
- Coordinate System
- Reading and Writing Image Files
Classes for Painting
These classes provide support for painting onto a paint device.
The QLine class provides a two-dimensional vector using integer precision. | |
The QLineF class provides a two-dimensional vector using floating point precision. | |
The QMargins class defines the four margins of a rectangle. | |
The QMarginsF class defines the four margins of a rectangle. | |
The QPoint class defines a point in the plane using integer precision. | |
The QPointF class defines a point in the plane using floating point precision. | |
The QRect class defines a rectangle in the plane using integer precision. | |
The QRectF class defines a rectangle in the plane using floating point precision. | |
The QSize class defines the size of a two-dimensional object using integer point precision. | |
The QSizeF class defines the size of a two-dimensional object using floating point precision. | |
The QStylePainter class is a convenience class for drawing QStyle elements inside a widget. | |
The QColormap class maps device independent QColors to device dependent pixel values. | |
Monochrome (1-bit depth) pixmaps | |
Scalable icons in different modes and states | |
Abstract base class for QIcon renderers | |
Hardware-independent image representation that allows direct access to the pixel data, and can be used as a paint device | |
Format independent interface for reading images from files or other devices | |
Format independent interface for writing images to files or other devices | |
Off-screen image representation that can be used as a paint device | |
Template class that represents a NxM transformation matrix with N columns and M rows | |
Represents a vector or vertex in 2D space | |
Defines the fill pattern of shapes drawn by QPainter | |
Used in combination with QBrush to specify gradient fills | |
Used in combination with QBrush to specify a linear gradient brush | |
Used in combination with QBrush to specify a radial gradient brush | |
Used in combination with QBrush to specify a conical gradient brush | |
Colors based on RGB, HSV or CMYK values | |
Represents a paintdevice that supports multiple pages | |
The base class of objects that can be painted on with QPainter | |
Abstract definition of how QPainter draws to a given device on a given platform | |
Performs low-level painting on widgets and other paint devices | |
Container for painting operations, enabling graphical shapes to be constructed and reused | |
Used to generate fillable outlines for a given painter path | |
Class to generate PDFs that can be used as a paint device | |
Defines how a QPainter should draw lines and outlines of shapes | |
Vector of points using integer precision | |
Vector of points using floating point precision | |
Specifies a clip region for a painter | |
Specifies 2D transformations of a coordinate system | |
Specifies a font used for drawing text | |
Font metrics information | |
Font metrics information | |
Used when registering fonts with the internal Qt fontdatabase |